The expression of the genomic repertoire of Escherichia coli is coordinately regulated in response to nutrient availability. This determines growth as well as the ability to survive prolonged periods of starvation. This project focuses on regulation of these processes in bacteria by analogs of of the common nucleotides GDP and GTP that possess ribosyl 3' pyrophosphate esters. This family of compounds is abbreviated collectively as (p)ppGpp. Intracellular levels of (p)ppGpp are altered in response to availability of amino acids, phosphate, nitrogen or energy; the (p)ppGpp signal, in turn, triggers globally altered patterns of gene expression related to the specific nutritional stress. In addition, (p)ppGpp recruits global domains of gene expression associated with stationary phase. This year we have found evidence of recruitment of cell cycle regulation domains and gene domains responding to the leucine regulatory protein (lrp) gene. Current evidence arising from mutant analyses is therefore beginning to define the extent of global regulatory domains directly or indirectly regulated by (p)ppGpp. So far, mutants that phenotypically mimic the presence of (p)ppGpp, when this nucleotide is actually absent, are found to occur only in three RNA polymerase subunit genes. We have previously described two "housekeeping" sigma mutants and their effects on premature RNA chain release during transcription initiation on model promoters. This year these effects are extended to suggest that physiologically relevant promoters responsible for synthesis of galactose or histidine are stimulated by the mutants by increasing promoter clearance efficiency. Attention is now given to other RNA polymerase mutants. We have mapped and identified the sequence changes for 59 different alleles of genes encoding the two large "core" RNA polymerase subunits (beta and beta'). In all, 52 new alleles have been documented. There is early evidence that these mutants do not regulate galactose promoters in the same way as previous sigma mutants. They are therefore of great interest.